Nano Express
Tailoring photonic metamaterial resonances for thermal radiation
Author affiliations
Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA
Citation and License
Nanoscale Research Letters 2011, 6:549 doi:10.1186/1556-276X-6-549
Published: 6 October 2011Abstract
Selective solar absorbers generally have limited effectiveness in unconcentrated sunlight, because of reradiation losses over a broad range of wavelengths and angles. However, metamaterials offer the potential to limit radiation exchange to a proscribed range of angles and wavelengths, which has the potential to dramatically boost performance. After globally optimizing one particular class of such designs, we find thermal transfer efficiencies of 78% at temperatures over 1,000°C, with overall system energy conversion efficiencies of 37%, exceeding the Shockley-Quiesser efficiency limit of 31% for photovoltaic conversion under unconcentrated sunlight. This represents a 250% increase in efficiency and 94% decrease in selective emitter area compared to a standard, angular-insensitive selective absorber.
PACS: 42.70.Qs; 81.05.Xj; 78.67.Pt; 42.79.Ek
